body {
  font-family: Arial, sans-serif;
  background: #f7f7f7;
  margin: 0;
  padding: 0;
}

.container {
  max-width: 600px;
  margin: 40px auto;
  background: white;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

.field {
  margin-bottom: 15px;
}

label {
  display: block;
  margin-bottom: 5px;
  font-weight: bold;
}

input {
  width: 100%;
  padding: 8px;
  box-sizing: border-box;
}

#preview-btn {
  margin-top: 20px;
  padding: 10px 15px;
  font-size: 16px;
}

#preview-box {
  background: #eee;
  padding: 15px;
  border-radius: 5px;
}